Roll-good fuel cell fabrication processes, equipment, and articles produced from same

ABSTRACT

Fabricating roll-good fuel cell material involves laminating first and second bonding material webs having spaced apart windows to first and second surfaces of a fuel cell membrane web. First and second active regions of the membrane web are positioned within the respective bonding material windows. Third and fourth gasket material webs having spaced apart windows are respectively laminated to the bonding material on the first and second membrane web surfaces. The bonding material windows align with the respective gasket material windows so that at least some of the bonding material extends within the respective gasket material windows. Fluid transport layer (FTL) material portions cut from fifth and sixth FTL material webs are laminated to the respective first and second active regions. The FTL material portions are positioned within respective gasket material windows and contact the bonding material extending within the respective gasket material windows.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. Ser. No. 10/446,485, filed May28, 2003, issued as U.S. Pat. No. 7,195,690, and a divisional of U.S.Ser. No. 11/676,586, filed Feb. 20, 2007, now allowed, the disclosure ofwhich is incorporated by reference in its entirety herein.

FIELD OF THE INVENTION

The present invention relates generally to fuel cells and, moreparticularly, to processes and apparatuses for automated fabrication ofmultiple layer fuel cell assemblies and sub-assemblies in roll-goodform, and fuel cell articles produced from same.

BACKGROUND OF THE INVENTION

Various apparatuses and methods have been developed to produce fuelcells from components developed in web or roll form. Conventionalassembling approaches typically involve cutting several of the input webcomponents to form stacks of such material in batch operations. Thesingulated materials are then manipulated using various mechanical andvacuum means to properly position the singulated materials during fuelcell assembly.

Although many of these processes can be automated, such approachestypically involve numerous handling, registration, and alignment stepsperformed by complex, time consuming, and typically expensive automationequipment. The number and complexity of processing steps associated withconventional fuel cell manufacturing approaches typically reducesproduct throughput, which negatively affects the productivity of anautomated fuel cell assembly line. Moreover, many conventional fuel cellfabrication apparatuses and methods are not well suited for a highdegree of automation, particularly such apparatus and processes whichhave tight positional tolerance requirements.

There is a need for improved fuel cell manufacturing apparatuses,methodologies, and fuel cell assemblies produced from such apparatusesand methodologies. There is a further need for such apparatuses,methodologies, and fuel cell assemblies that can be implemented in anautomated assembly environment, such as in an automated fuel cellassembly plant. The present invention fulfills these and other needs,and addresses other deficiencies in prior approaches.

SUMMARY OF THE INVENTION

The present invention is directed to improved fuel cell fabricationprocesses, equipment, and articles produced from same. The presentinvention is further directed to automated fabrication of multiple layerfuel cell assemblies and sub-assemblies in roll-good form, includingunitized fuel cell assemblies in roll-good form.

In accordance with one embodiment of the present invention, a method ofcontinuously producing a multiple layer web of fuel cell materialinvolves laminating first and second webs, each comprising bondingmaterial and having spaced apart windows, to first and second surfacesof a web comprising a fuel cell membrane. First and second activeregions of the membrane web are positioned within the respective bondingmaterial windows. The method further involves laminating third andfourth webs, each comprising a gasket material and having spaced apartwindows, respectively to the bonding material disposed on the first andsecond surfaces the membrane web. The windows of the bonding materialalign with the respective windows of the gasket material so that atleast some of the bonding material extends within the respective gasketmaterial windows. The method also involves laminating fluid transportlayer (FTL) material portions cut from fifth and sixth webs comprisingFTL material to the respective first and second active regions of themembrane web. The FTL material portions are positioned within respectivegasket material windows and contact the bonding material extendingwithin the respective gasket material windows.

According to another embodiment, a method of continuously producing amultiple layer web of fuel cell material for use with and between a pairof flow field plates or between gasket layers involves cutting a firstweb comprising bonding material to produce spaced apart first windows inthe first web. The first windows include bonding sites provided along aperiphery of the first windows. A second web comprising bonding materialis cut to produce spaced apart second windows in the second web. Thesecond windows also include bonding sites provided along a periphery ofthe second windows.

The method further involves providing a web comprising a fuel cellmembrane having active regions disposed on respective first and secondsurfaces of the membrane web, and laminating a first surface of thefirst bonding material web to the first surface of the membrane web sothat the active regions of the first surface of the membrane web arepositioned within the first windows. A first surface of the secondbonding material web is laminated to the second surface of the membraneweb so that the active regions of the second surface of the membrane webare positioned within the second windows. The method also involveslaminating FTL material portions cut from fourth and fifth webscomprising FTL material to the active regions of the respective firstand second surfaces of the membrane web. Each of the FTL materialportions contact the bonding sites of the respective first and secondwindows.

In accordance with a further embodiment, a method of continuouslyproducing multiple layer fuel cell assemblies involves processing a webof membrane material, a first bonding web, and a first web comprisingFTL material to form a first surface of a membrane electrode assembly(MEA) web. The method also involves processing the web of membranematerial, a second bonding web, and a second web comprising FTL materialto form a second surface of the MEA web. First and second flow fieldplates are provided, preferably in the form of first and second flowfield plate webs. The method further involves encasing each MEA of theMEA web between a respective pair of the first and second flow fieldplates.

According to another embodiment, a method of continuously producingmultiple layer fuel cell assemblies involves producing a continuous MEAweb. A first web comprising bonding material having spaced apart firstwindows is provided, wherein the first windows include bonding sitesprovided along a periphery of the first windows. A second web comprisingbonding material having spaced apart second windows is provided. Thesecond windows include bonding sites provided along a periphery of thesecond windows. A web comprising a fuel cell membrane having activeregions disposed on respective first and second surfaces of the membraneweb is also provided.

The method also involves laminating a first surface of the first bondingmaterial web to the first surface of the membrane web so that the activeregions of the first surface of the membrane web are positioned withinthe first windows, and laminating a first surface of the second bondingmaterial web to the second surface of the membrane web so that theactive regions of the second surface of the membrane web are positionedwithin the second windows. FTL material portions cut from fourth andfifth webs comprising FTL material are laminated to the active regionsof the respective first and second surfaces of the membrane web, whereineach of the FTL material portions contact the bonding sites of therespective first and second windows.

The method further involves providing a continuous web of first flowfield plates and providing a continuous web of second flow field plates.Each of the MEAs is encased between a respective pair of the first andsecond flow field plates.

In accordance with yet another embodiment, an apparatus for continuouslyproducing a multiple layer web of fuel cell material includes a firstcutting station configured for cutting a first web comprising bondingmaterial. The first cutting station includes a first cutting mechanismconfigured to produce spaced apart first windows in the first web. Thefirst windows include bonding sites provided along a periphery of thefirst windows. A second cutting station is configured for cutting asecond web comprising bonding material. The second cutting stationincludes a second cutting mechanism configured to produce spaced apartsecond windows in the second web. The second windows include bondingsites provided along a periphery of the second windows.

The apparatus also includes a membrane web transport mechanismconfigured to transport a membrane web. The membrane web comprises afuel cell membrane having active regions disposed on respective firstand second surfaces of the membrane web. A first laminating station isconfigured to laminate a first surface of the first bonding material webto the first surface of the membrane web so that the active regions ofthe first surface of the membrane web are positioned within the firstwindows. A second laminating station is configured to laminate a firstsurface of the second bonding material web to the second surface of themembrane web so that the active regions of the second surface of themembrane web are positioned within the second windows.

The apparatus further includes a third laminating station configured tolaminate first FTL patches to the active regions of the first surface ofthe membrane web, such that each of the first FTL patches contact thebonding sites of the first windows. A fourth laminating station isconfigured to laminate second FTL patches to the active regions of thesecond surface of the membrane web, such that each of the second FTLpatches contact the bonding sites of the second windows.

According to a further embodiment, a fuel cell assembly includes amembrane having a first surface and a second surface. The first andsecond surfaces include first and second active regions, respectively. Afirst bonding layer includes a first surface in contact with the firstsurface of the membrane and comprises a first window in alignment withthe first active region of the membrane. The first window includesprotrusions of bonding material in contact with the first active region.

A second bonding layer of the fuel cell assembly has a first surface incontact with the second surface of the membrane and includes a secondwindow in alignment with the second active region of the membrane. Thesecond window includes protrusions of bonding material in contact withthe second active region.

A first gasket layer is disposed on a second surface of the firstbonding layer and includes a third window in alignment with the firstwindow of the first bonding layer. A second gasket layer is disposed ona second surface of the second bonding layer and includes a fourthwindow in alignment with the second window of the second bonding layer.

The fuel cell assembly also includes a first FTL in contact with thefirst surface of the membrane, wherein a peripheral edge of the firstFTL contacts at least the bonding material protrusions of the firstwindow. A second FTL is in contact with the second surface of themembrane, such that a peripheral edge of the second FTL contacts atleast the bonding material protrusions of the second window. An anodecatalyst is disposed at one of the first and second active regions, anda cathode catalyst is disposed at the other of the first and secondactive regions.

In accordance with another embodiment, a fuel cell sub-assembly for usewith and between a pair of flow field plates or between gasket layersincludes a membrane having a first surface and a second surface. Thefirst and second surfaces includes first and second active regions,respectively. A first bonding layer has a first surface in contact withthe first surface of the membrane and includes a first window inalignment with the first active region of the membrane. The first windowincludes protrusions of bonding material in contact with the firstactive region. A second bonding layer of the fuel cell sub-assembly hasa first surface in contact with the second surface of the membrane andincludes a second window in alignment with the second active region ofthe membrane. The second window includes protrusions of bonding materialin contact with the second active region.

The fuel cell sub-assembly also includes a first FTL in contact with thefirst surface of the membrane, wherein a peripheral edge of the firstFTL contacts at least the bonding material protrusions of the firstwindow. A second FTL is in contact with the second surface of themembrane, wherein a peripheral edge of the second FTL contacts at leastthe bonding material protrusions of the second window. An anode catalystis disposed at one of the first and second active regions, and a cathodecatalyst is disposed at the other of the first and second activeregions.

The above summary of the present invention is not intended to describeeach embodiment or every implementation of the present invention.Advantages and attainments, together with a more complete understandingof the invention, will become apparent and appreciated by referring tothe following detailed description and claims taken in conjunction withthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a typical fuel cell and its basic operation;

FIG. 2 is an illustration of a multiple layer fuel cell assemblyconstructed in accordance with an embodiment of the present invention;

FIG. 3 is a cross-sectional view of the fuel cell assembly shown in FIG.2;

FIG. 4 is an illustration of a multiple layer fuel cell assemblyconstructed in accordance with another embodiment of the presentinvention;

FIG. 5 is an illustration of a multiple layer fuel cell assemblyconstructed as a unitized fuel cell assembly or UCA in accordance withanother embodiment of the present invention;

FIGS. 6-9 are flow diagrams that illustrate various processes forfabricating fuel cell assemblies, sub-assemblies, and unitized fuel cellassemblies in accordance with embodiments of the present invention;

FIG. 10 shows an embodiment of an apparatus for priming a fuel cellmembrane web and attaching various fuel cell components thereto inaccordance with a continuous fuel cell manufacturing process of thepresent invention;

FIG. 11 shows an embodiment of an apparatus for attaching fluidtransport layer (FTL) patches cut from FTL material webs to a primedmembrane web in accordance with a continuous fuel cell manufacturingprocess of the present invention;

FIG. 12 illustrates a single apparatus that incorporates the apparatusesof FIGS. 10 and 11;

FIG. 13 illustrates an embodiment of a sealing apparatus for sealingfuel cell assemblies and sub-assemblies in accordance with a continuousfuel cell manufacturing process of the present invention;

FIG. 14A is an illustration of a molding station and process forproducing flow field plates in accordance with a continuous fuel cellmanufacturing process of the present invention;

FIGS. 14B and 14C illustrate features of a molded living hingearrangement for producing a continuous web of flow field plates inaccordance with a continuous fuel cell manufacturing process of thepresent invention;

FIG. 15 illustrates features of a molded carrier strip arrangement forproducing a continuous web of flow field plates in accordance with acontinuous fuel cell manufacturing process of the present invention;

FIGS. 16A and 16 B illustrate features of another molded interlockingarrangement for producing a continuous web of flow field plates inaccordance with a continuous fuel cell manufacturing process of thepresent invention; and

FIG. 17 is an illustration of a molding system and process for producingmolded unitized fuel cell assemblies in accordance with a continuousfuel cell manufacturing process of the present invention.

While the invention is amenable to various modifications and alternativeforms, specifics thereof have been shown by way of example in thedrawings and will be described in detail. It is to be understood,however, that the intention is not to limit the invention to theparticular embodiments described. On the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

In the following description of the illustrated embodiments, referenceis made to the accompanying drawings which form a part hereof, and inwhich is shown by way of illustration, various embodiments in which theinvention may be practiced. It is to be understood that the embodimentsmay be utilized and structural changes may be made without departingfrom the scope of the present invention.

The present invention is directed to improved methods and apparatusesfor constructing fuel cell structures, and to improved fuel cellassemblies. A fuel cell is an electrochemical device that combineshydrogen fuel and oxygen from the air to produce electricity, heat, andwater. Fuel cells do not utilize combustion, and as such, fuel cellsproduce little if any hazardous effluents. Fuel cells convert hydrogenfuel and oxygen directly into electricity, and can be operated at muchhigher efficiencies than internal combustion electric generators, forexample.

A typical fuel cell is depicted in FIG. 1. The fuel cell 10 shown inFIG. 1 includes a first fluid transport layer (FTL) 12 adjacent an anode14. Adjacent the anode 14 is an electrolyte membrane 16. A cathode 18 issituated adjacent the electrolyte membrane 16, and a second fluidtransport layer 19 is situated adjacent the cathode 18. The FTLs 12 and19 can be referred to as diffuse current collectors (DCCs) or gasdiffusion layers (GDLs). In operation, hydrogen fuel is introduced intothe anode portion of the fuel cell 10, passing through the first fluidtransport layer 12 and over the anode 14. At the anode 14, the hydrogenfuel is separated into hydrogen ions (H⁺) and electrons (e⁻).

The electrolyte membrane 16 permits only the hydrogen ions or protons topass through the electrolyte membrane 16 to the cathode portion of thefuel cell 10. The electrons cannot pass through the electrolyte membrane16 and, instead, flow through an external electrical circuit in the formof electric current. This current can power an electric load 17, such asan electric motor, or be directed to an energy storage device, such as arechargeable battery.

Oxygen flows into the cathode side of the fuel cell 10 via the secondfluid transport layer 19. As the oxygen passes over the cathode 18,oxygen, protons, and electrons combine to produce water and heat.

A number of individual fuel cells, such as that shown in FIG. 1, can beproduced from roll-good input materials (e.g., webs of fuel cellcomponents) in accordance with the principles of the present invention.For example, individual fuel cells can be fabricated using a continuousassembling approach by which roll-good input web materials are processedto produce a roll-good output web of complete fuel cell assemblies. Incertain approaches, roll-good input web materials can be processed toproduce a roll-good output web of fuel cell sub-assemblies, which can beused in a subsequent process to produce complete fuel cell assemblies.

Output fuel cell assembly and sub-assembly webs can be wound withappropriate liner material to form a roll. In another approach, outputfuel cell assembly and sub-assembly webs can be subject to a singulationprocess, by which individual fell cell assemblies or sub-assemblies areseparated from their respective webs.

According to other approaches, roll-good fuel cell input web materialsand flow field plates can be processed to produce unitized fuel cellassemblies (UCAs) in a continuous manner. A unitized fuel cell assemblyis a unitary module or unit that comprises one or more cells that canwork as a functioning fuel cell alone or in conjunction with other UCAsin a stack. UCAs can be implemented in a monopolar or bipolarconfiguration.

In one approach, for example, roll-good fuel cell input web materialsand webs of flow field plates can be processed to produce a web of UCAs.The webs of flow field plates can be produced using an in-line moldingprocess by which flow field plates are molded during, before, or afterfuel cell web processing and are used to encase membrane electrodeassemblies (MEAs) of the output web. UCAs can be rolled or singulatedand stacked for ease of handling and future use.

A number of different fuel cell technologies can be employed toconstruct fuel cell assemblies, sub-assemblies, and UCAs in accordancewith the principles of the present invention. For example, a fuel cellfabrication methodology of the present invention can be employed toconstruct proton exchange membrane (PEM) fuel cell assemblies andsub-assemblies. PEM fuel cells operate at relatively low temperatures(about 175° F./80° C.), have high power density, can vary their outputquickly to meet shifts in power demand, and are well suited forapplications where quick startup is required, such as in automobiles forexample.

The proton exchange membrane used in a PEM fuel cell is typically a thinplastic sheet that allows hydrogen ions to pass through it. The membraneis typically coated on both sides with highly dispersed metal or metalalloy particles (e.g., platinum or platinum/ruthenium) that are activecatalysts. The electrolyte used is typically a solid organic polymersuch as poly-perfluorosulfonic acid. Use of a solid electrolyte isadvantageous because it reduces corrosion and management problems.

Hydrogen is fed to the anode side of the fuel cell where the catalystpromotes the hydrogen atoms to release electrons and become hydrogenions (protons). The electrons travel in the form of an electric currentthat can be utilized before it returns to the cathode side of the fuelcell where oxygen has been introduced. At the same time, the protonsdiffuse through the membrane to the cathode, where the hydrogen ions arerecombined and reacted with oxygen to produce water.

A membrane electrode assembly (MEA) is the central element of PEM fuelcells, such as hydrogen fuel cells. As discussed above, typical MEAscomprise a polymer electrolyte membrane (PEM) (also known as an ionconductive membrane (ICM)), which functions as a solid electrolyte.

One face of the PEM is in contact with an anode electrode layer and theopposite face is in contact with a cathode electrode layer. Eachelectrode layer includes electrochemical catalysts, typically includingplatinum metal. Fluid transport layers (FTLs) facilitate gas transportto and from the anode and cathode electrode materials and conductelectrical current.

In a typical PEM fuel cell, protons are formed at the anode via hydrogenoxidation and transported to the cathode to react with oxygen, allowingelectrical current to flow in an external circuit connecting theelectrodes. The FTL may also be called a gas diffusion layer (GDL) or adiffuser/current collector (DCC). The anode and cathode electrode layersmay be applied to the PEM or to the FTL during manufacture, so long asthey are disposed between PEM and FTL in the completed MEA.

Any suitable PEM may be used in the practice of the present invention.The PEM typically has a thickness of less than 50 μm, more typicallyless than 40 μm, more typically less than 30 μm, and most typicallyabout 25 μm. The PEM is typically comprised of a polymer electrolytethat is an acid-functional fluoropolymer, such as Nafion® (DuPontChemicals, Wilmington Del.) and Flemion® (Asahi Glass Co. Ltd., Tokyo,Japan). The polymer electrolytes useful in the present invention aretypically preferably copolymers of tetrafluoroethylene and one or morefluorinated, acid-functional comonomers.

Typically, the polymer electrolyte bears sulfonate functional groups.Most typically, the polymer electrolyte is Nafion®. The polymerelectrolyte typically has an acid equivalent weight of 1200 or less,more typically 1100 or less, more typically 1050 or less, and mosttypically about 1000.

Any suitable FTL may be used in the practice of the present invention.Typically, the FTL is comprised of sheet material comprising carbonfibers, such as a carbon fiber paper. The FTL is typically a carbonfiber construction selected from woven and non-woven carbon fiberconstructions. Carbon fiber constructions which may be useful in thepractice of the present invention may include: Toray Carbon Paper,SpectraCarb Carbon Paper, AFN non-woven carbon cloth, Zoltek CarbonCloth, and the like. The FTL may be coated or impregnated with variousmaterials, including carbon particle coatings, hydrophilizingtreatments, and hydrophobizing treatments such as coating withpolytetrafluoroethylene (PTFE).

Any suitable catalyst may be used in the practice of the presentinvention. Typically, carbon-supported catalyst particles are used.Typical carbon-supported catalyst particles are 50-90% carbon and 10-50%catalyst metal by weight, the catalyst metal typically comprising Pt forthe cathode and Pt and Ru in a weight ratio of 2:1 for the anode. Thecatalyst is typically applied to the PEM or to the FTL in the form of acatalyst ink. The catalyst ink typically comprises polymer electrolytematerial, which may or may not be the same polymer electrolyte materialwhich comprises the PEM.

The catalyst ink typically comprises a dispersion of catalyst particlesin a dispersion of the polymer electrolyte. The ink typically contains5-30% solids (i.e. polymer and catalyst) and more typically 10-20%solids. The electrolyte dispersion is typically an aqueous dispersion,which may additionally contain alcohols, polyalcohols, such a glycerinand ethylene glycol, or other solvents such as N-methylpyrolidone (NMP)and dimethylformamide (DMF). The water, alcohol, and polyalcohol contentmay be adjusted to alter rheological properties of the ink. The inktypically contains 0-50% alcohol and 0-20% polyalcohol. In addition, theink may contain 0-2% of a suitable dispersant. The ink is typically madeby stirring with heat followed by dilution to a coatable consistency.

The catalyst may be applied to the PEM or the FTL by any suitable means,including both hand and machine methods, including hand brushing, notchbar coating, fluid bearing die coating, wire-wound rod coating, fluidbearing coating, slot-fed knife coating, three-roll coating of bothanode and cathode formulations, or decal transfer of the dried catalystcoatings onto the membrane. Coating may be achieved in one applicationor in multiple applications.

Another fuel cell technology that can be employed to construct fuel cellassemblies, sub-assemblies, and UCAs in accordance with the principlesof the present invention is referred to as direct methanol fuel cell.Direct methanol fuel cells (DMFC) are similar to PEM cells in that theyboth use a polymer membrane as the electrolyte. In a DMFC, however, theanode catalyst itself draws the hydrogen from liquid methanol fuel,eliminating the need for a fuel reformer. DMFCs typically operate at atemperature between 120-190° F./49-88° C. A direct methanol fuel cellcan be subject to processing and packaging in accordance with theprinciples of the present invention.

Referring now to FIG. 2, there is illustrated an embodiment of amultiple layer fuel cell 37 in accordance with a PEM fuel celltechnology. A cross-sectional view of the fuel cell embodiment of FIG. 2is provided in FIG. 3. The fuel cell 37 shown in FIGS. 2 and 3 is a7-layer structure, which includes a 5-layer MEA and a 2-layer gasketstructure.

The fuel cell 37 includes a PEM layer 30 having surfaces to whichbonding layers 32 and 42 are respectively applied. Although the bondinglayers 32 and 42 are depicted as discrete members in FIG. 2, it isunderstood that bonding layers 32 and 42 can be formed using a solid, aliquid, or a UV or light curable material or a vaporous bonding materialor agent.

The bonding layers 32 and 42 are patterned or otherwise formed toinclude a window having a size about equal to the active region of thePEM layer 30. The windows of the bonding layers 32 and 42 include anumber of inwardly extending bonding sites 33, 43. The bonding sites 33,43 extend into the active area of the PEM layer 30 and serve tofacilitate adhering contact between the active regions of the PEM layer30 and respective fluid transport layers (FTLs) 36 and 46, whileminimizing ingression of the bonding layers 32 and 42 into the activeregions of the PEM layer 30. Use of bonding sites to provide adheringcontact between the PEM layer 30 and FTLs 36 and 46 can advantageouslyeliminate the need to subject these layers to compressive press forcesat elevated temperatures for a prolonged period of time as in the caseof traditional processing techniques.

In FIG. 2, the bonding sites 33, 43 are shown as a series of protrusionsor fingers provided about the inner periphery of the bonding layerwindows. It is understood that the bonding sites can be formed orpatterned to take on a number of different configurations, and that thefinger shaped bonding sites 33, 43 shown in FIG. 2 and elsewhere are forillustrative, non-limiting purposes only. For example, the bonding sites33, 43 can define a number of edge portions of the inner periphery ofthe bonding layer windows. Also, the bonding sites 33, 43 can define acontinuous inner peripheral edge of the bonding layer windows. These andother configurations can be employed as bonding sites 33, 43, suchbonding sites contacting only a small percentage of the total activearea of the PEM layer 30, such as no greater than about 15%.

Gasket layers 34 and 44 are situated to contact respective bondinglayers 32 and 42. The gasket layers 34 and 44 include windows having asize larger than the widows of the bonding layers 32 and 42. The gasketlayers 34 and 44 can be formed from a variety of materials, including,for example, TEFLON, fiberglass impregnated with TEFLON, an elastomericmaterial, UV curable polymeric material, surface texture material,multi-layered composite material, sealants, and silicon material.

In one particular embodiment, the gasket layers 34 and 44 may each be aclosed-cell foam rubber gasket as disclosed in co-pending applicationSer. No. 10/294,098, filed Nov. 14, 2002 under Attorney Docket58218US002 and incorporated herein by reference. In other embodiments,the gasket layers 34 and 44 may be formed with a contact face having araised-ridge microstructured sealing pattern as disclosed in co-pendingapplication Ser. No. 10/143,273, filed May 10, 2002, and incorporatedherein by reference.

The FTLs 36 and 46 are sized to fit within the windows of the gasketlayers 34 and 44. Moreover, the FTLs 36 and 46 are sized to cover theinner peripheral edge of the windows of bonding layers 32 and 42, inaddition to covering the bonding sites 33 and 43. Anode catalystmaterial (not shown) is situated between one of the two FTLs 36, 46 andthe PEM layer 30, and cathode catalyst material (not shown) is situatedbetween the PEM layer 30 and the other of the two FTLs 36, 46.

In one configuration, the PEM layer 30 is fabricated to include an anodecatalyst coating on one surface and a cathode catalyst coating on theother surface. This structure is often referred to as a catalyst-coatedmembrane or CCM. According to another configuration, the FTLs 36, 46 arefabricated to include an anode and cathode catalyst coating,respectively. In yet another configuration, an anode catalyst coatingcan be disposed partially on one of the two FTLs 36, 46 and partially onone surface of the PEM layer 30, and a cathode catalyst coating can bedisposed partially on the other of the two FTLs 36, 46 and partially onthe other surface of the PEM layer 30.

The PEM layer 30 and FTLs 36 and 46 can have a construction as discussedabove. The bonding layers 32 and 42 can be formed using a thermobondmaterial, such as a thermosetting or a thermoplastic material.Appropriate bonding layer materials include pressure sensitiveadhesives, bonding agents, self-sealing materials, and heat-activatedbonding materials.

According to one embodiment, the bonding layers 32 and 46 are formedusing a thermoplastic sealing material. The thermoplastic can be afluoroplastic like THV (terpolymer of tetrafluoroethylene,hexafluoropropylene and vinylidene difluoride); polyethylene; copolymersof polyethylene such as those of ethylene and acrylic acid; Thermo-Bond845 (manufactured by 3M, e.g., a polyethylene maleic anhydridecopolymer) and Thermo-Bond 668 (manufactured by 3M, e.g., a polyester).Blends of these materials or composite materials of these with fillerssuch as carbon, glass, ceramic, etc. may also be used as thermoplastics.Preferably, the melt range is 50-180° C., and more preferably 100-150°C., which should be similar to the MEA bonding temperature.

FIG. 4 is an illustration of a fuel cell sub-assembly 35 in accordancewith an embodiment of the present invention. The fuel cell sub-assembly35 depicted in FIG. 4 is a unique 5-layer MEA structure thatincorporates bonding layers on opposing surfaces of the membrane. Asshown, the MEA of FIG. 4 incorporates several of the layers and featurespreviously described in connection with the fuel cell assembly of FIGS.2 and 3. In particular, the MEA of FIG. 4 includes a PEM layer 30 havingsurfaces to which bonding layers 32 and 42 are respectively applied. Aspreviously described, the bonding layers 32 and 42 include a windowhaving a size about equal to the active region of the PEM layer 30.

The windows of the bonding layers 32 and 42 include a number of inwardlyextending bonding sites or fingers 33, 43. The bonding sites 33, 43extend into the active area of the PEM layer 30 and adheringly contactportions of the active regions of the PEM layer 30 and respective fluidtransport layers (FTLs) 36 and 46. The FTLs 36 and 46 are sized to fitwithin the windows of the gasket layers 34 and 44, and cover the innerperipheral edge of the windows of bonding layers 32 and 42, in additionto covering the bonding sites 33 and 43. An anode is situated betweenone of the two FTLs 36, 46 and the PEM layer 30, and a cathode issituated between the PEM layer 30 and the other of the two FTLs 36, 46.

In this embodiment, the surfaces of the bonding layers 32, 42 not incontact with the PEM layer 30 are preferably covered by a liner (notshown) or other material so that the bonding material of the bondinglayers 32, 42 and the FTLs 36, 46 are not exposed until such time asexposure of same is desired in a subsequent process. Various types ofrelease liners can be used for this purpose. In a subsequent process,the exposed bonding layers 32, 42 and FTLs 36, 46 may be registered withrespective gasket layers or flow field plates, for example.

MEA structures of the type shown in FIG. 4 can be stored in appropriatemanner for use in subsequent fuel cell fabrication processes, such as inthe form of a roll-good or in stacks. Alternatively, these MEAstructures can be subject to further automated fuel cell assemblingprocesses, such as those described below. In cases where a release lineris used, as is discussed above, the release liner can be removed fromthe outer surfaces of the bonding layers/FTLs, such as by an automatedprocess. It is noted that certain bonding materials need not beprotected using a liner, such as in the case of a fuel cell assemblyroll-good that incorporates certain thermobond materials.

By way of example, and with reference to FIG. 5, there is illustrated anembodiment of a UCA in which an MEA 35 of the type described above isdisposed between a pair of flow field plates 50 and 60. According tothis embodiment, the MEA 35 includes a PEM layer 30 sandwiched betweenbonding layers 32 and 42 each having a window about equal in size to theactive region of the PEM layer 30 and inwardly extending bonding sitesor fingers 33, 43 as previously described. Two FTLs 36 and 46 are sizedto fit within the windows of the gasket layers 34 and 44, and cover theinner peripheral edge of the windows of bonding layers 32 and 42, inaddition to covering the bonding sites 33 and 43. Anode and cathoderegions are respectively situated between the two FTLs 36, 46 and thePEM layer 30, as previously discussed.

Each of the bonding layers 32 and 42 shown in FIG. 5 has an exposedbonding surface which can be registered with a surface of a respectiveflow field plate 50, 60. Bonding contact between the exposed bondingsurfaces of the bonding layers 32 and 42 a respective flow field plates50 and 60 advantageously maintains accurate registration between thesecomponents during automated fuel cell assembly. Moreover, the bondinglayers 32 and 42 can facilitate edge sealing of the UCA during a heatedsealing process. UCA fabrication processes and structures which mayincorporate process and structural features of the present invention aredisclosed in co-pending application Ser. Nos. 10/295,518 and 10/295,292filed concurrently on Nov. 15, 2002 and incorporated herein byreference.

In general terms, each of the flow field plates 50, 60 includes a fieldof gas flow channels and ports through which hydrogen and oxygen feedfuels pass. In certain configurations, the flow field plates 50, 60 canbe configured as monopolar flow field plates, in which a single MEA 35is sandwiched between a pair of flow field plates 50, 60 to define aUCA. The flow field in this and other embodiments may be a low lateralflux flow field as disclosed in co-pending application Ser. No.09/954,601, filed Sep. 17, 2001, and incorporated herein by reference.In a typical configuration, the size of the flow field plates aretypically about the same size as the membrane.

In other configurations, a UCA can incorporate multiple MEAs 35 throughemployment of one or more bipolar flow field plates. For example, a UCAcan incorporate two MEAs 35 of the type described in FIG. 5 and a singlebipolar flow field plate. In such a configuration, a first MEA 35 caninclude a bonding layer/cathode/membrane/anode/bonding layer structuresandwiched between first and second FTLs. The first FTL can be situatedadjacent a first flow field end plate, which can be configured as amonopolar flow field plate. The second FTL can be situated adjacent afirst flow field surface of bipolar flow field plate.

Similarly, a second MEA 35 can include a bondinglayer/cathode/membrane/anode/bonding layer structure sandwiched betweenthird and fourth FTLs. The third FTL can be situated adjacent a flowfield end plate, which can be configured as a monopolar flow fieldplate. The fourth FTL can be situated adjacent a second flow fieldsurface of the bipolar flow field plate. It will be appreciated that Nnumber of MEAs 35 and N−1 bipolar flow field plates can be incorporatedinto a single UCA. It is believed, however, that, in general, a UCAincorporating one or two MEAs 35 is preferred for more efficient thermalmanagement.

The UCA configurations shown in FIG. 5 and discussed herein arerepresentative of particular arrangements that can be implemented foruse in the context of the present invention. These arrangements areprovided for illustrative purposes only, and are not intended torepresent all possible configurations coming within the scope of thepresent invention. For example, an in-line molding process for producingflow field plates as described below may dictate use of certain UCAfeatures, such as additional or enhanced sealing features, gasketfeatures, and/or hard and soft stop features. Conversely, such anin-line molding process may provide for elimination of certain UCAfeatures, such as elimination of a separate gasket or sealing feature bysubstitute use of material molded around the manifolds of the flow fieldplates.

By way of further example, a variety of enhanced sealing methodologiescan be employed to provide the requisite sealing of a UCA comprising asingle MEA disposed between a pair of monopolar flow field plates, andcan also be employed to seal a UCA comprising multiple MEAs, a pair ofmonopolar flow field plates and one or more bipolar flow field plates.For example, a UCA having a monopolar or bipolar structure can beconstructed to incorporate an in-situ formed solid gasket, such as aflat solid silicone gasket disclosed in previously incorporatedapplication Ser. Nos. 10/295,518 and 10/295,292.

In particular embodiments, a UCA can further incorporate a hard stoparrangement. The hard stop(s) can be built-in, disposed internal to theUCA, or integrated into the monopolar and/or bipolar flow field plates.Other features can be incorporated into a UCA, such as an excess gasketmaterial trap channel and a micro replicated pattern provided on theflow field plates. Incorporating a hard stop into the UCA packagingadvantageously limits the amount of compressive force applied to the MEAduring fabrication (e.g., press forces) and during use (e.g., externalstack pressure system). For example, the height of a UCA hard stop canbe calculated to provide a specified amount of MEA compression, such as30%, during UCA construction, such compression being limited to thespecified amount by the hard stop. Incorporating a hard stop into theflow field plates can also act as a registration aid for the two flowfield plates.

Moreover, a variety of UCA configurations can be implemented with athermal management capability in accordance with other embodiments ofthe present invention. By way of example, a given UCA configuration canincorporate an integrated thermal management system. Alternatively, oradditionally, a given UCA can be configured to mechanically couple witha separable thermal management structure. Several exemplary UCA hardstop and thermal management approaches are disclosed in previouslyincorporated application Ser. Nos. 10/295,518 and 10/295,292.

FIGS. 6-9 depict various methodologies by which fuel cell assemblies andsub-assemblies can be produced in accordance with embodiments of thepresent invention. FIG. 6 illustrates various processes involving thecontinuous production of roll-good or singulated fuel cellsub-assemblies, such as MEAs, using roll-good input fuel cell materials.According to the embodiment of FIG. 6, a web of a membrane material,such as a web of PEM material, is processed 70 together with a first webof a bonding material to form a first bonding surface of the membraneweb. A second surface of the membrane web is processed 72 with a secondbonding material web to form a second bonding surface of the membraneweb.

The first bonding surface of the membrane web is processed 74 togetherwith a first web of a gasket material to form gaskets on the firstbonding surface of the membrane web. The second bonding surface of themembrane web is processed 76 with a second gasket material web to formgaskets on the second bonding surface of the membrane web.

The first bonding surface of the membrane web is further processed 78together with FTL material portions to form a first fuel cellsub-assembly web surface. The second bonding surface of the membrane webis processed 80 together with FTL material portions to form a secondfuel cell sub-assembly web surface.

The FTL material portions are preferably provided from first and secondFTL material webs which are processed with the first and second bondingsurfaces of the membrane web to form the first and second fuel cellsub-assembly web surfaces, respectively. The first and second fuel cellsub-assembly web surfaces formed on first and second surface of themembrane web define a web of MEA structures, such as that shown as MEA37 in FIGS. 2-3.

The fuel cell sub-assembly web is transferred 82 for further processing,such as to a winding process to produce a fuel cell sub-assemblyroll-good or to a singulation process to produce singulated fuel cellsub-assembly sheets. It is noted that a liner is typically in contactwith the otherwise exposed bonding material surfaces of the membrane websurfaces for enhancing handling and transportability.

FIG. 7 illustrates various processes for producing a web of fuel cellsub-assemblies, such as MEAs, in accordance with another embodiment.According to this approach, first and second bonding material webs eachwith windowed sections are provided 90. A liner is provided on onesurface of the first and second bonding surfaces, respectively. Theexposed surfaces of the windowed first and second bonding material websare laminated 92 to first and second surfaces of a membrane web. FTLmaterial portions are positioned 94 at active regions of the membraneweb such that the FTL material portions will contact exposed bondingsites within the windows of the bonding material webs.

The FTL material portions are then laminated 96 to the active regions ofthe first and second surfaces of the membrane web, thus forming a web ofMEA structures, such as that shown as MEA 35 in FIG. 4. The multi-layerfuel cell sub-assembly web is further processed 98 to produce a fuelcell sub-assembly roll-good or singulated fuel cell sub-assembly sheets.

FIG. 8 illustrates various processes for producing a web of fuel cellsub-assemblies which incorporates gasket layers in accordance with afurther embodiment of the present invention. According to thisembodiment, the windows of first and second bonding material webs arealigned 100 with active regions of a membrane web. The windowed firstand second bonding material webs are laminated 102 to respective firstand second surface of a membrane web. The windows of third and fourthgasket material webs are aligned 104 with first and second activeregions of the membrane web. The third and fourth windowed gasketmaterial webs are laminated 106 to the bonding material on the first andsecond membrane web surfaces.

FTL material portions are positioned 108 at the active regions of thefirst and second membrane web surfaces to contact bonding sites definedwithin the windows of the first and second bonding material webs. TheFTL material portions are then laminated 110 to the active regions ofthe first and second membrane web surfaces. The processes depicted inFIG. 8 can be employed to the produce an MEA which incorporates gasketmaterial layers, such as MEA 37 illustrated in FIGS. 2 and 3. As inpreceding embodiments, the multi-layer fuel cell sub-assembly webproduced in accordance with FIG. 8 can be further processed to produce afuel cell sub-assembly roll-good or singulated fuel cell sub-assemblysheets.

FIG. 9 illustrates various processes involving the production ofunitized fuel cell assemblies or UCAs in accordance with an embodimentof the present invention. According to this approach, a membrane web, afirst bonding material web, and a first FTL web are processed 120 toform a first surface of a fuel cell sub-assembly web. The membrane web,a second bonding material web, and a second FTL web are processed 122 toform a second surface of the fuel cell sub-assembly web.

A series of first flow field plates (e.g., monopolar or bipolar) ispositioned 124 for contacting the first surface of the fuel cellsub-assembly web. A series of second flow field plates is positioned 126for contacting the second surface of the fuel cell sub-assembly web. Inparticular, pairs of first and second flow field plates are positionedfor contacting individual fuel cell sub-assemblies formed on the fuelcell sub-assembly web. The pairs of first and second flow field platesand individual fuel cell sub-assemblies are processed 128 to formunitized fuel assemblies, such as a web of UCAs.

The UCAs, in web form or singulated form, can be further processed toseal individual UCAs, such as by use of a heated press procedure. Theprocesses depicted in FIG. 9 can be employed to the produce a UCA of thetype illustrated in FIG. 5. A web of such UCAs can be further processedto produce a UCA roll-good or singulated UCAs.

The processes described above are provided for illustrative purposesonly, and are not intended to represent all possible processes forproducing fuel cell assemblies, sub-assemblies, and UCAs coming withinthe scope of the present invention. Moreover, processes in addition to,or different from, those described above can be employed to produce fuelcell assemblies, sub-assemblies, and UCAs of the present invention. Forexample, the apparatuses and associated processes described below can beemployed to produce fuel cell assemblies, sub-assemblies, and UCAs ofthe present invention.

Turning now to FIGS. 10-12, there is illustrated apparatuses thatprocess input webs of fuel cell materials and produce an outputroll-good of fuel cell assemblies, sub-assemblies, or UCAs from suchinput webs. In general terms, the apparatuses of FIGS. 10-12 can producea roll-good of fuel cells using roll-good fuel cell components. Theapparatus of FIG. 10 provides a unique approach to priming an ionomerfuel cell membrane web for purposes of attaching various fuel cellcomponents thereto, such as gasket and FTL components, in a continuousfuel cell manufacturing process. The apparatus of FIG. 11 provides aunique approach to attaching FTL material portions cut from FTL materialwebs to primed membranes in a continuous fuel cell manufacturingprocess. FIG. 12 illustrates a single apparatus that incorporates theapparatuses of FIGS. 10 and 11.

The apparatus of FIG. 10 laminates a patterned bonding agent from aliner to the fuel cell membrane web. The bonding material patternspreferably have substantially the same shape and area as the catalystactive areas of the fuel cell membrane web. In addition, according toone embodiment, gasket material is attached to the fuel cell membraneweb subsequent to priming, which provides for excellent membrane webstability needed for continuous assembling of fuel cell components. Thebonding material typically has a thickness of between about 1 and 6 mil.

As is shown in FIG. 10, a first roll of bonding material on a liner 212a is die-cut by a rotary die 234 a and anvil roll 240 a to produce apatterned (e.g., windowed) web of bonding material. Waste bondingmaterial on the liner 218 a is collected, such as by a vacuum process.The patterned bonding material web 212 a is laminated to the top surfaceof a membrane web 210 via nip roll 238 a. Hence, the laminated membraneweb has a patterned bonding agent and liner on its top surface 222.

A second roll of bonding material on a liner 212 b is also die-cut by arotary die 234 b and anvil roll 240 b and laminated to the bottom faceof the membrane web 210 via nip roll 238 b, resulting in a liner/bondingmaterial/membrane/bonding material/liner construction 224. Waste bondingmaterial on the liner 218 b is collected.

Optical sensors are preferably used to align the bonding material webpatterns (e.g., windows) on both the top and bottom surfaces of themembrane web 210. The fiber optic sensors can, for example, detect thewindow of the bonding material pattern relative to the active regions onboth sides of the membrane web 210.

Those skilled in the art will appreciate that several techniques andconfigurations can be employed to facilitate windowed material alignmentusing optical sensors or other types of sensing arrangements. By way ofexample, one optical sensor can be positioned to detect the pattern cutfrom die 234 a after it is laminated at the nip formed by rolls 240 aand 238 a and before the nip formed by rolls 240 b and 238 b. A secondoptical sensor can be positioned to detect a mark on or attached to dieroll 234 b, where a mark corresponds to each die cavity.

Another optical sensing approach involves positioning a first sensor todetect a mark on or attached to die roll 234 a, where the markcorresponds to each cavity, and positioning a second sensor to detect amark on or attached to die roll 234 b, where this mark corresponds toeach cavity. Yet another approach involves mechanically tying rolls 234a and 234 b together, with the ability to phase adjust roll 234 b suchthat the die cuts are laminated to web 210 in register.

The liner of the patterned bonding material web is peeled off and woundon a waste liner roll 214 a. Removal of this liner provides for a web226 having an exposed bonding material/membrane/bonding material/linerconstruction. A roll of gasket material 216 a is die-cut by a firstrotary die 236 a and anvil roll 240 c, with waste gasket material 220 acollected using vacuum or other approach. The die cut gasket material isroll laminated to the top surface of the exposed bondingmaterial/membrane laminate 226 via nip roll 238 c forming agasket/bonding material/membrane/bonding material/liner laminate 228.

The liner of the bottom side of laminate 228 is also peeled off andwound on waste liner roll 214 b, forming laminate 230. Laminate 230 hasa gasket/bonding material/membrane/bonding material construction. Asecond roll of gasket material 216 b is die-cut by a second rotary die236 b and anvil roll 240 d, with waste gasket material 220 b collectedusing a vacuum or other approach. The die cut gasket material is rolllaminated to the bottom surface of the exposed bonding material oflaminate 230 via nip roll 238 d forming a gasket/bondingmaterial/membrane/bonding material/gasket laminate 232.

In accordance with this embodiment, the apparatus of FIG. 10 produces afuel cell membrane having a gasket material held to top and bottomsurfaces of the membrane by use of a bonding material (e.g., bondingagent or an adhesive) exposed as a window pattern on the bare membrane.It is noted that some of the patterned bonding material remains exposedon the membrane because the gasket die-cut waste 220 a, 220 b isslightly larger than the bonding material die-cut waste 218 a, 218 b.

It is preferable that the first die-cut that produces laminate 230 bethe master registration signal for the rest of the process. Each diewould register to the web. The die roll should be driven separately fromthe anvil roll at each station since the anvil roll is also acting as anip. It is noted that web tensions typically run in the 1 to 2 pli(pounds per lineal inch) range, but this tension range could be as lowas from 0.1 pli to 3 pli.

The apparatus illustrated in FIG. 10 provides for several advantagesover conventional fuel cell fabrication approaches. One advantageconcerns a unique process of priming an ionomer membrane film (inroll-form) and concurrently attaching fuel cell components thereto tomanufacture a multi-layer (e.g., 7-layer) fuel cell assembly in acontinuous fuel cell manufacturing process. Another advantage concernspresence of a bonding material or agent on the membrane and exposed atthe edge of the catalyst area due to use of a gasket material attachedto the membrane having a window (die cut) larger than the exposedcatalyst area. A further advantage concerns the roll-good membrane filmmaterial becoming more stable for continuous membrane processing due tothe tougher gasket material attached to it.

Other advantages concern a bonding material exposed at the edge of theactive catalyst area which is used to attach conductive fluid transportlayer (FTL) material as part of a multi-layer fuel cell assemblingprocess. Such bonding material exposed at the edge of active area canalso be used to seal gases from leaking through the FTL of the fuel cellassembly.

FIG. 11 illustrates an apparatus that attaches roll-good FTL material toan already primed fuel cell membrane web in a continuous manufacturingprocess. For example, the apparatus of FIG. 10 discussed above and theapparatus of FIG. 11 can be combined to define a single apparatus forconstructing a multi-layer fuel cell assembly using roll-good processingtechniques. FIG. 12 is an illustration of single apparatus that combinesthe priming and FTL material attachment apparatuses of FIGS. 10 and 11.

The apparatus of FIG. 11 attaches roll-good FTL material to the membranefilm at the edge of the catalyst active area. Since the FTL material isattached only at the edge of the catalyst active area, there is no decayin fuel cell performance. In general, FTL material portions are cut froman FTL material web by a rotary die. Each FTL material portion is heldon the die surface by a vacuum and placed precisely within the gasketand/or bonding material window of the membrane web. Bonding materialpreviously provided on the membrane web contacts the FTL materialportions to affix the FTL material portions to the active regions of themembrane web.

The apparatus of FIG. 11 can be employed to place FTL material portionsto a membrane web using a number of methods. It is assumed that laminate232 (gasket/bonding material/membrane/bonding material/gasket laminate)shown in FIG. 10 is input to the apparatus shown in FIG. 11. Accordingto one approach, rotary dies 254 a, 254 b each have a pattern that isthe exact shape of the desired part. The dies 254 a, 254 b turn at a 1:1web speed match, as well as a 1:1 die 254 a/254 b to anvil roll 258a/258 b speed ratio, respectively.

A first web of FTL material 256 a is fed to a first rotary die roll 254a and anvil roll 258 a via nip roll 259 a. The die roll 254 a ispreferably a vacuum die roll. The die roll 254 a holds the cut FTL partvia vacuum until it is laminated to the top surface of laminate 232 toproduce an excellent catalyst/FTL interface in addition to a laminate250 having an FTL/gasket/bonding material/membrane/bondingmaterial/gasket construction. Waste FTL material is wound on a wasteroll (not shown).

Similarly, a second web of FTL material 256 b is fed to a second rotarydie roll 254 b and anvil roll 258 b via nip roll 259 b. The die roll 254b holds the cut FTL part via vacuum until it is laminated to the bottomsurface of laminate 250 to produce laminate 252. Laminate 252 has anFTL/gasket/bonding material/membrane/bonding material/gasket/FTLconstruction.

According to another method using the apparatus of FIG. 11, a rotary die254 a/254 b and a special anvil roll 258 a/258 b are configured as amatched set. In this regard, the die 254 a/254 b and anvil roll 258a/258 b are designed to allow the die roll surface speed to anvil rollsurface speed ratio to be equivalent to the fuel cell part size to FTLpart size ratio.

To achieve this objective, the FTL webs 256 a, 256 b are held onrespective anvil rolls 258 a, 258 b by vacuum, and FTL web speed iscontrolled by the nip formed by respective anvil rolls 258 a, 258 b andrubber nip rolls 259 a, 259 b. The die rolls 254 a, 254 b turn at ahigher surface speed, but do not pull the respective FTL webs 256 a, 256b. When a die blade comes around, the FTL webs 256 a, 256 b are cut andthe cut FTL parts are held on the die rolls 254 a, 254 b by vacuum.There is a separation between the cut FTL and the FTL web 256 a, 256 bdue to the surface speed difference between the respective die and anvilrolls, 254 a/254 b and 258 a/258 b. The die blades are registered to themembrane web (232 and 250) by fiber optic sensors and servo controlleddie stations.

Each cut FTL part is placed in the center of an associated gasketwindow. In one configuration, registration of the FTL parts within thecenter of the gasket windows is monitored by optical sensors, such asfiber optic sensor. By way of example, and with reference to FIG. 11,one sensor would pick up windows on the web 232 and a second sensorwould be positioned to pick up a mark on or attached to the die roll 254a where the mark corresponds to each die cavity. A third sensor would bepositioned to pick up a mark on or attached to the die roll 254 b.

According to a preferred approach, the window cut in the bondingmaterial web is the smallest in size. The gasket window is the largestin size, and the FTL patch is cut to fit inside the gasket window andcompletely cover the edge of the bonding material window. Each FTL patchcontacts bonding sites protruding inwardly from the inner periphery of acorresponding bonding material window.

The FTL attachment apparatus illustrated in FIG. 11 advantageously cutsroll-good FTL material, holds a die-cut FTL piece by a vacuum, andprecisely places the FTL piece within a window of a fuel cell gasket ina continuous fabrication process. It may be desirable to attach one ormore layers of thin foam material (e.g., having a thickness of 2 mils)to the rotary steel die of the die stations such that vacuum can bebetter maintained on the FTL material when it is cut. It may be furtherdesirable to use only outer holes of the rotary die to enhanceperformance of the vacuum die. It is noted that the protrusions of theedges of the die-cut FTL patches should be controlled and maintained tominimum levels so that no tearing of the membrane occurs when attachingthe FTL to the gasket window of the membrane.

FIG. 13 illustrates an additional web processing station that can beused to promote sealing of the laminate 252 produced at the output ofthe apparatus shown in FIG. 12. It is noted that the apparatuscomponents shown left of drum 260 in FIG. 13 are those depicted in FIG.12. As discussed previously, the laminate 252 has an FTL/gasket/bondingmaterial/membrane/bonding material/gasket/FTL construction. In theembodiment illustrated in FIG. 13, a drum 260 having a relatively largeradius is preferably heated to an appropriate temperature sufficient toactivate the bonding material of the laminate 252 and also to providefor a good catalyst/FTL interface. A roll 262 and the drum 260 cooperateto place the laminate 252 under tension as the laminate 252 rolls aboutthe outer surface of the drum. The tension developed between thelaminate 252 and the drum 260 serves to place the laminate structureunder a controlled amount of pressure during the heat sealing process.

The size of the drum 260, speed of laminate rotation, total contact timebetween the laminate 252 and drum surface, and amount of tension areamong several processing parameters that can be selected to achieve anappropriate level of laminate sealing and also an excellent catalyst/FTLinterface. These processing parameters can be adjusted to optimizelaminate sealing based on the particular materials used in the laminateconstruction. It can be appreciated that a sealing apparatus of the typeillustrated in FIG. 13 provides for enhanced flexibility in terms offuel cell material selection and performance characteristics. It will beappreciated that other sealing apparatuses can be employed to furtherprocess the laminate 252. Other such sealing apparatuses include thosethat employ UV curing, heat (e.g., curing ovens), RF activation, ande-beam activation, for example.

As was discussed previously, a roll-good fuel cell web, such as oneproduced in accordance with the above-described embodiments, can befurther processed by a molding station to encase individual fuel cellassemblies of the fuel cell web between pairs of flow field plates. Inone approach, and as shown in FIG. 14A, a molding station 300 can beconfigured to receive a web of fuel cell assemblies. The molding station300 includes two mold halves, 302 and 304, which move relative to oneanother via conventional mold/clamp mechanisms. In the embodiment shownin FIG. 14A, the upper mold half 302 is movable in the vertical planerelative to the stationary lower mold half 304. The lower and upper moldhalves in this configuration include the mold cavities. It is noted thatthe mold halves can include a single mold cavity or multiple moldcavities.

In general, one or more fuel cell assemblies of the input web aretransported between the upper and lower mold halves 302, 304. Each fuelcell assembly is registered with a mold cavity. Registration sensors,such as optical sensors, can be used to ensure proper alignment of thefuel cell assemblies with their respective mold cavities. The upper moldhalf 302 is moved into engagement with the lower mold half 304 undercompressive forces produced by a clamp mechanism of the molding station300. A material appropriate for the construction of flow field plates isintroduced into the mold cavities. The material may be injected or addedas a preform, for example.

After completion of the shot and expiration of an appropriate curingduration, the upper mold half 302 is moved upwardly from, and out ofengagement with, the lower mold half 304. The encased fuel assemblies(i.e., UCA) are then removed from the mold cavities of the lower moldhalf 304. It is noted that a release agent can be sprayed or otherwisedispensed onto the surface of the upper and lower mold cavity halves topromote easy separation of the molded UCAs from the mold cavities. It isfurther noted that color agents, UV protection agents, and other agentscan be introduced into the injected material or sprayed into the moldcavities to enhance the aesthetics and/or durability of the molded UCAs.

The input fuel cell web can be received in roll-good form produced by anautomated continuous web processing approach as described above. It isunderstood, however, that an in-line flow field plate molding approachof the present invention can be used to encase roll-good or singulatefuel cell assemblies produced in other manners.

In another approach, for example, the input fuel cell web to the moldingstation 300 can be the laminate 252 produced at the output of theapparatus shown in FIG. 12 or FIG. 13. According to this approach, anintermediary staging station may be required to coordinate any web speeddifferential between the output of the apparatuses of FIG. 12 or FIG. 13and the input of the molding station 300. Preferably, any such speeddifferential can be minimized by matching molding rates (which includeshot time and curing duration) at the molding station 300 with webprocessing rates of the apparatuses of FIG. 12 or FIG. 13.

According to another embodiment, the molding station 300 can beconfigured to mold flow field plates into a continuous web, with aliving hinge, carrier strip, or other interlocking arrangement, such asa tapered hole and plug arrangement, provided between adjacent plates.The molding material can also perform the gasket function around themanifolds of the flow field plates.

As can be seen in FIGS. 14B and 14C, the molds can be designed to allowfor an overmold of the material onto itself to form a bond with thepreviously molded plate, thus forming a continuous web of flow fieldplates. FIG. 14B shows a first portion 310 of the living hinge at therear of flow field plate 306 at a time t₁ in the molding station 300.FIG. 14C shows a second portion 312 of the living hinge which is createdto engage the first portion 310 by overmolding material from the nextadjacent flow field plate 308 into the first portion 310 of thepreviously molded flow field plate 306 at a time t₂ in the moldingstation. The living hinge geometry (314) shown in FIG. 14C allows forconnectivity between adjacent flow field plates and flexing of the web.The depression 314 is formed between adjacent flow field plates toenhance flexing of the web and singulation of individual UCAs from theweb of UCAs.

In accordance with another approach, the molding station 300 isconfigured with mold halves that produce carrier strips to connectadjacent plates in a continuous web, as is shown in FIG. 15. In oneapproach, the flow field plates 400 and carrier strips 402 a, 402 b aremolded using a first shot. After this first shot, a narrow gap separatesthe flow field plates 400 and carrier strips 402 a, 402 b. A secondovermold shot injects material into this narrow gap to connect the flowfield plates 400 with the carrier strips 402 a, 402 b. Registrationholes can be formed in the carrier strips 402 a, 402 b to facilitatesubsequent winding and/or singulation processes.

FIGS. 16A and 16B illustrate yet another approach to molding flow fieldplates to form a continuous web. According to this approach, a reversetaper hole 502 is molded into a corner of a first flow field plate 500 aduring a first shot. During a second overmold shot that forms anadjacent flow field plate 500 b, material from the second shot is flowedinto at least the reverse taper hole 502 of the previously molded plate500 a to form a plug 504. This hold and plug interlocking arrangementcan be formed at each corner of adjacent flow field plates 500 a, 500 b.

A web of flow field plates produced in accordance with the presentinvention can be rolled up as a roll-good for future assembly.Alternatively, and as shown in FIG. 17, webs of flow field plates can befed directly into a UCA assembly line, in which case two presses may beused, each making a web for each side of the UCA as show in FIG. 17.

The UCA assembly station 600 shown in FIG. 17 includes a first moldingstation 601 that produces a first web of flow field plates 606, and asecond molding station 603 that produces a second web of flow fieldplates 608. An MEA web 606 is transported so that individual MEAs 604 aof the MEA web 604 register with a pair of flow field plates 606 a, 608a from the first and second flow field plate webs 606, 608. Afterencasing the MEAs 606 a between respective pairs of flow field plates606 a, 608 a, the resulting UCA web 610 may be further processed by asealing stations and/or a winding station. A web 610 of sealed UCAs cansubsequently be subject to a singulation process to separate individualUCAs from the UCA web 610.

The foregoing description of the various embodiments of the inventionhas been presented for the purposes of illustration and description. Itis not intended to be exhaustive or to limit the invention to theprecise form disclosed. Many modifications and variations are possiblein light of the above teaching. For example, the various rotary cutting,laminating, and transporting processes described with reference to theaccompanying figures can instead be accomplished using non-rotarymethods and apparatuses, such as by use of flat die processes andapparatuses, step and repeat processes and apparatuses, pick and placeprocesses and apparatuses, intermittent motion processes andapparatuses, and index and stamp cut processes and apparatuses as areknown in the art, for example. It is intended that the scope of theinvention be limited not by this detailed description, but rather by theclaims appended hereto.

1. A method of continuously producing multiple layer fuel cellassemblies, comprising: processing a web of membrane material, a firstbonding web, and a first web comprising fluid transport layer (FTL)material to form a first surface of a membrane electrode assembly (MEA)web; processing the web of membrane material, a second bonding web, anda second web comprising FTL material to form a second surface of the MEAweb; providing first flow field plates; providing second flow fieldplates; and encasing each MEA of the MEA web between a respective pairof the first and second flow field plates.
 2. The method according toclaim 1, wherein: providing the first and second flow field platescomprises providing a first web comprising the first flow field platesand a second web comprising the second flow field plates; and the methodfurther comprises registering the first and second webs with the MEAweb.
 3. The method according to claim 1, wherein providing the first andsecond flow field plates further comprises: providing a first webcomprising the first flow field plates; and providing a second webcomprising the second flow field plates.
 4. The method according toclaim 1, wherein providing the first and second flow field platesfurther comprises: molding a polymeric material to produce the firstflow field plates; and molding the polymeric material to produce thesecond flow field plates.
 5. The method according to claim 1, whereinproviding the first and second flow field plates further comprises:molding a polymeric material to produce a first web of the first flowfield plates; and molding the polymeric material to produce a second webof the second flow field plates.
 6. An apparatus for continuouslyproducing a multiple layer web of fuel cell material, comprising: afirst cutting station configured for cutting a first web comprisingbonding material, the first cutting station comprising a first cuttingmechanism configured to produce spaced apart first windows in the firstweb, the first windows comprising bonding sites provided along aperiphery of the first windows; a second cutting station configured forcutting a second web comprising bonding material, the second cuttingstation comprising a second cutting mechanism configured to producespaced apart second windows in the second web, the second windowscomprising bonding sites provided along a periphery of the secondwindows; a membrane web transport mechanism configured to transport amembrane web, the membrane web comprising a fuel cell membrane havingactive regions disposed on respective first and second surfaces of themembrane web; a first laminating station configured to laminate a firstsurface of the first bonding material web to the first surface of themembrane web so that the active regions of the first surface of themembrane web are positioned within the first windows; a secondlaminating station configured to laminate a first surface of the secondbonding material web to the second surface of the membrane web so thatthe active regions of the second surface of the membrane web arepositioned within the second windows; a third laminating stationconfigured to laminate first fluid transport layer (FTL) patches to theactive regions of the first surface of the membrane web, each of thefirst FTL patches contacting the bonding sites of the first windows; anda fourth laminating station configured to laminate second FTL patches tothe active regions of the second surface of the membrane web, each ofthe second FTL patches contacting the bonding sites of the secondwindows.
 7. The apparatus according to claim 6, wherein the first andsecond cutting mechanisms respectively comprise a rotary cutting die anda rotary anvil.
 8. The apparatus according to claim 6, wherein the firstand second laminating stations respectively comprise nip rolls.
 9. Theapparatus according to claim 8, wherein the first and second cuttingmechanisms respectively comprise a rotary cutting die and a rotaryanvil, the respective rotary anvils serving as one of the nip rolls forthe respective first and second laminating stations.
 10. The apparatusof claim 6, further comprising: a third cutting station configured toreceive a first web of FTL material, the third cutting stationcomprising a third cutting mechanism configured to cut the first FTLpatches from the first FTL material web; and a fourth cutting stationconfigured to receive a second web of FTL material, the fourth cuttingstation comprising a fourth cutting mechanism configured to cut thesecond FTL patches from the second FTL material web.
 11. The apparatusaccording to claim 10, wherein the third and fourth cutting mechanismsrespectively comprise a rotary cutting die and a rotary anvil.
 12. Theapparatus according to claim 10, wherein the third and fourth laminatingstations respectively comprise nip rolls.
 13. The apparatus according toclaim 12, wherein the third and fourth cutting mechanisms respectivelycomprise a rotary cutting die and a rotary anvil, the respective rotaryanvils serving as one of the nip rolls for the respective third andfourth laminating stations.
 14. The apparatus according to claim 6,further comprising: a fifth laminating station configured to laminate afirst gasket material web to the first bonding material web on the firstmembrane web surface; and a sixth laminating station configured tolaminate a second gasket material web to the second bonding material webon the second membrane web surface.
 15. The apparatus according to claim14, further comprising: a fifth cutting station comprising a fifthcutting mechanism configured to cut spaced apart windows in the firstgasket material web; and a sixth cutting station comprising a sixthcutting mechanism configured to cut spaced apart windows in the secondgasket material web.
 16. The apparatus according to claim 15, whereinthe fifth and sixth cutting mechanisms respectively comprise a rotarycutting die and a rotary anvil.
 17. The apparatus according to claim 15,wherein the fifth and sixth laminating stations respectively comprisenip rolls.
 18. The apparatus according to claim 17, wherein the fifthand sixth cutting mechanisms respectively comprise a rotary cutting dieand a rotary anvil, the respective rotary anvils serving as one of thenip rolls for the respective fifth and sixth laminating stations. 19.The apparatus according to claim 6, further comprising a sealing stationconfigured to receive the produced web of fuel cell material, thesealing station subjecting the fuel cell material web to heat andpressure.
 20. The apparatus according to claim 19, wherein the sealingstation comprises a sealing drum and a tension roll, the produced web offuel cell material contacting an outer periphery of the sealing drumunder pressure via cooperation between the sealing drum and the tensionroll.
 21. The apparatus according to claim 6, further comprising amolding system, the molding system comprising: first and second moldingstations, the first molding station configured to mold a polymericmaterial to produce first flow field plates, the second molding stationconfigured to mold a polymeric material to produce second flow fieldplates; and an assembly station configured to encase each MEA of theproduced web of fuel cell material between a respective pair of thefirst and second flow field plates.
 22. The apparatus according to claim21, wherein the first and second molding stations are configured toproduce continuous webs of the first and second flow field plates. 23.The apparatus according to claim 22, wherein the first and secondmolding stations are configured to form a living hinge between adjacentones of the first flow field plates and between adjacent ones of thesecond flow field plates.
 24. The apparatus according to claim 22,wherein the first and second molding stations are configured to formcarrier strips along opposing sides of the first flow field plates andalong opposing sides of the second flow field plates.
 25. The apparatusaccording to claim 21, wherein the first and second molding stations areconfigured to form a plug and hole interlocking arrangement at cornersof adjacent ones of the first flow field plates and at corners ofadjacent ones of the second flow field plates.
 26. The method accordingto claim 6, further comprising a winding station configured to wind theproduced web of fuel cell material into a roll.
 27. The method accordingto claim 6, further comprising a singulation station configured tosingulate the produced web of fuel cell material into discrete fuel cellmaterial sheets.
 28. A fuel cell assembly, comprising: a membranecomprising a first surface and a second surface, the first and secondsurfaces comprising first and second active regions, respectively; afirst bonding layer having a first surface in contact with the firstsurface of the membrane and comprising a first window in alignment withthe first active region of the membrane, the first window comprisingprotrusions of bonding material in contact with the first active region;a second bonding layer having a first surface in contact with the secondsurface of the membrane and comprising a second window in alignment withthe second active region of the membrane, the second window comprisingprotrusions of bonding material in contact with the second activeregion; a first gasket layer disposed on a second surface of the firstbonding layer and comprising a third window in alignment with the firstwindow of the first bonding layer; a second gasket layer disposed on asecond surface of the second bonding layer and comprising a fourthwindow in alignment with the second window of the second bonding layer;a first fluid transport layer (FTL) in contact with the first surface ofthe membrane, a peripheral edge of the first FTL contacting at least thebonding material protrusions of the first window; a second FTL incontact with the second surface of the membrane, a peripheral edge ofthe second FTL contacting at least the bonding material protrusions ofthe second window; an anode catalyst disposed at one of the first andsecond active regions; and a cathode catalyst disposed at the other ofthe first and second active regions.
 29. The assembly according to claim28, wherein the protrusions of bonding material of the first and secondwindows define a plurality of edge portions of the first and secondwindows, respectively.
 30. The assembly according to claim 28, whereinthe plurality of edge portions define a continuous peripheral edge ofthe first and second windows, respectively.
 31. The assembly accordingto claim 28, wherein the protrusions of bonding material of the firstand second windows define a plurality of inwardly projecting fingersdisposed along a peripheral edge of the first and second windows,respectively.
 32. The assembly according to claim 28, wherein the firstand second bonding layers comprise a heat-activated bonding.
 33. Theassembly according to claim 28, wherein the first and second bondinglayers comprise a thermobonding material.
 34. The assembly according toclaim 28, wherein the first and second bonding layers comprise apressure sensitive bonding.
 35. The assembly according to claim 28,wherein the first and second bonding layers comprise a bonding agent.36. The assembly according to claim 28, wherein the first and secondbonding layers comprise a light-curable bonding agent.
 37. The assemblyaccording to claim 28, wherein the third and fourth windows of the firstand second gaskets are larger than first and second windows of the firstand second bonding layers, respectively.
 38. The assembly according toclaim 28, wherein a plurality of the fuel cell assemblies are arrangedto define a web of fuel cell assemblies.
 39. The assembly according toclaim 28, wherein the fuel cell assembly defines a proton exchangemembrane fuel cell assembly.
 40. A fuel cell sub-assembly for use withand between a pair of flow field plates or between gasket layers,comprising: a membrane comprising a first surface and a second surface,the first and second surfaces comprising first and second activeregions, respectively; a first bonding layer having a first surface incontact with the first surface of the membrane and comprising a firstwindow in alignment with the first active region of the membrane, thefirst window comprising protrusions of bonding material in contact withthe first active region; a second bonding layer having a first surfacein contact with the second surface of the membrane and comprising asecond window in alignment with the second active region of themembrane, the second window comprising protrusions of bonding materialin contact with the second active region; a first fluid transport layer(FTL) in contact with the first surface of the membrane, a peripheraledge of the first FTL contacting at least the bonding materialprotrusions of the first window; a second FTL in contact with the secondsurface of the membrane, a peripheral edge of the second FTL contactingat least the bonding material protrusions of the second window; an anodecatalyst disposed at one of the first and second active regions; and acathode catalyst disposed at the other of the first and second activeregions.
 41. The sub-assembly according to claim 40, further comprising:a first flow field plate in contact with the first FTL and a secondsurface of the first bonding layer; and a second flow field plate incontact with the second FTL and a second surface of the second bondinglayer.
 42. The assembly according to claim 40, wherein the protrusionsof bonding material of the first and second windows define a pluralityof edge portions of the first and second windows, respectively.
 43. Theassembly according to claim 42, wherein the plurality of edge portionsdefine a continuous peripheral edge of the first and second windows,respectively.
 44. The assembly according to claim 40, wherein theprotrusions of bonding material of the first and second windows define aplurality of inwardly projecting fingers disposed along a peripheraledge of the first and second windows, respectively.
 45. The assemblyaccording to claim 40, wherein the first and second bonding layerscomprise a heat-activated bonding.
 46. The assembly according to claim40, wherein the first and second bonding layers comprise a thermobondingmaterial.
 47. The assembly according to claim 40, wherein the first andsecond bonding layers comprise a pressure sensitive bonding.
 48. Theassembly according to claim 40, wherein the first and second bondinglayers comprise a bonding agent.
 49. The assembly according to claim 40,wherein the first and second bonding layers comprise a light-curablebonding agent.
 50. The assembly according to claim 40, wherein aplurality of the fuel cell sub-assemblies are arranged to define a webof fuel cell sub-assemblies.
 51. The assembly according to claim 40,wherein the fuel cell sub-assembly defines a proton exchange membranefuel cell sub-assembly.